Before it was a school, the Lyceum was a sanctuary. The name comes from Apollo Lyceus - Apollo the wolf-god - to whom the grounds were dedicated, just outside the eastern edge of ancient Athens near the Ilissos river. It was a place of training and gathering long before any philosopher claimed it. Athenian soldiers mustered here when Sparta raided the countryside during the Peloponnesian War. The Assembly met on these grounds before moving to the Pnyx. The gymnasium, where young men exercised, may have been built by the tyrant Pisistratus in the sixth century BC or by Pericles in the fifth - the tradition is divided, but the antiquity is not in doubt. It was a public space soaked in the daily rhythms of the city, athletic and military and civic all at once.

Philosophers were drawn here generations before Aristotle. Socrates walked the road from the Academy to the Lyceum in Plato's dialogue Lysis. Protagoras and Prodicus debated on the grounds; Isocrates taught rhetoric here in the fourth century BC. Then, in 335 BC, Aristotle returned to Athens at the age of forty-nine - he had been away tutoring a Macedonian prince who would become Alexander the Great - and set up his own school in one of the Lyceum's buildings. He taught in the mornings and lectured to the public afterward, and he did it while walking. His followers strolled the covered walkways, the peripatoi, as they argued, and so the school earned its name: the Peripatetics, the people who paced. To picture Aristotle is to picture a man in motion, working out the structure of the entire world one footstep at a time.

Aristotle was a collector by temperament, and the Lyceum became a research institution unlike anything before it. He gathered books on a scale no Greek had attempted, building what later writers called the first true library in Europe, and he organized his students to study every subject then known - biology, politics, ethics, music, the history of mathematics. One ancient observer compared the school to a factory that turned out professionals of every kind. The library's later fate was almost a thriller. Aristotle's successor Theophrastus willed the books to a man named Neleus, who carted them off to a town in Asia Minor, where they vanished for centuries. Recovered and shipped to Rome after the general Sulla sacked Athens in 86 BC, roughly a fifth of Aristotle's writings were lost along the way - which is why the works we read today are the survivors of a long, bruising journey.

The school itself faded after Sulla's assault, and its exact location became a scholarly guess. Ancient writers placed it vaguely east of the old city, near the Ilissos and below Lycabettus Hill, but no one could point to the spot - until the 1996 dig for the Goulandris Museum of Modern Art forced the question. Archaeologists were certain of what they had found: the foundations rest directly on bedrock with no earlier layers beneath, exactly as the original Lyceum should. The excavation revealed the gymnasium, the wrestling area, changing rooms and baths - the bones of Aristotle's academy. Plans for the museum were reworked so the ruins could be preserved and shared, and in 2009 the site opened as a public park at the junction of Rigillis and Vasilissis Sofias Streets, beside the War Museum. You can now walk where the Peripatetics walked, on the ground where Western philosophy first learned to think out loud.